A Levels Chemistry (9701)•9701/13/O/N/23
Explanation
Inductive effect enhances basicity of ethoxide ion
Steps:
- Examine products: ethanol + Na yields CH3CH2O-, water + Na yields OH-.
- Assess basicity: stronger base indicates weaker conjugate acid, affecting deprotonation rate.
- Consider substituents: ethyl group in ethoxide exerts +I effect, donating electrons to oxygen.
- Conclude: higher electron density on oxygen makes CH3CH2O- stronger base than OH-.
Why B is correct:
- Electron-donating inductive effect (+I) of alkyl group increases negative charge density on oxygen, strengthening basicity per organic chemistry inductive effects.
Why the others are wrong:
- A: Incomplete and restates the stem without explanation.
- C: Ethoxide charge is localized on oxygen, not delocalized like in resonance-stabilized ions.
- D: Ethanol (pKa 15.9) is less acidic than water (pKa 15.7), so harder to deprotonate.
Final answer: B
Topic: Hydroxy compounds
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